1. Field of the Invention
The present invention relates to a method of treating depression or depression-related disorders. More specifically, the invention relates to a method of treating depression and depression-related disorders by administration of compounds that increase astrocyte glutamate transport, such as KATP channel openers and/or compounds capable of stimulating glutamate transporter expression.
2. Background of the Invention
It is the rare individual who has not been beset, at least once in his or her life, with a bout of sadness or “the blues” leading to an inability to perform daily tasks with the usual vigor and little enjoyment in life. In most cases, these occurrences are brought on by recognizable events, such as a divorce, loss of a loved one, or work-related stress. In most cases, these occurrences pass after a reasonable period of time and the individual returns to a normal routine. However, for many such individuals, that normal routine never returns, but rather the individual's routine becomes depression. In extreme cases, the condition becomes so severe that the individual becomes completely unable to cope with the relatively minor stresses of everyday life. Often such individuals are overwhelmed by feelings of fatigue, hopelessness, worthlessness, guilt, and thoughts of suicide.
Although to date no single cause of clinical depression has been identified, it is now generally accepted that there is likely a neurochemical component to it. Typical treatments now often consist of a combination of psychotherapy and medication. Currently, the most commonly used antidepressant medications function generally to regulate brain neurotransmitters such as dopamine, serotonin and norepinephrine. Two classes of compounds, one known as selective serotonin reuptake inhibitors, or SSRIs, and the other known as serotonin and norepinephrine reuptake inhibitors (SNRIs) are widely prescribed for treatment of depression. These antidepressants, such as fluoxetine (Prozac®), sertraline (Zoloft®), venlafaxine (Effexor®) and duloxetine (Cymbalta®) have gained substantial popularity because they cause fewer side effects than earlier antidepressants, such as monoamine oxidase inhibitors (MAOIs). Notwithstanding their improved tolerability, however, SSRIs and SNRIs still cause their share of side effects, including insomnia, nausea and sexual dysfunction. In addition to the associated problems, a major concern with known antidepressants is the time they take to achieve their desired effect. In most cases, it will be a minimum of three to four weeks before a full relief of symptoms is observed. In the case of severe depression, this delay can sometimes be life-threatening. Furthermore, only about two-thirds of patients treated actually respond to modern antidepressants. Thus, there continues to be a need for development of new antidepressant medications that will avoid some or all of the problems observed with those antidepressants currently in use. Based on a novel observation regarding the neurochemical basis for depression, the present invention fills such a need.